The equation given is \( c = 9.4b \), where \( c \) is the total cost in dollars and cents and \( b \) is the number of boxed lunches ordered.
To find the cost per boxed lunch, we can divide the total cost \( c \) by the number of boxed lunches \( b \):
\[ \text{Cost per boxed lunch} = \frac{c}{b} = \frac{9.4b}{b} \]
Since \( b \) is not zero, we can simplify this to:
\[ \text{Cost per boxed lunch} = 9.4 \]
Therefore, the cost per boxed lunch is $9.40.